Endo, Semi-auto, Cytoskeleton (Lecture 5) Flashcards
What are lysosomes?
- like cell’s stomach
- formed by budding off golgi
- hydrolysis both internal and external stuff:
-
internal: organelles that are old and/or not functioning correctly. Termed autophagy
-external: bacteria and debris engulfed by phagocytosis - not present in plants
Where are vacuoles present?
Plants and fungi
What are vacuoles functions?
- turgor pressure for cell enlargement
- storage of nutrients
- maintain ion gradients
- digest waste products (similar to lysosomes)
- sometimes contain pigments
- some protists also have specialized vacuoles
What are semi-autonomous organelles?
- mitochondria
- chloroplasts
Although surrounded by membranes, they are not part of the endomembrane system because they do not send or receive vesicles
How are semi-autonomous organelles involved in generation and usage of bio energy?
Also, what does the mitochondria and and chloroplasts go through? What do they use/ byproducts
- both use electrochemical reactions to make energy
- both have internal membranes with extensive folding to increase the surface area of the energy producing machinery
Mitochondria - (sugars + O2) -> undergoes respiration -> (ATP + H2O)
Chloroplasts - (CO2 + H2O0 -> undergoes photosynthesis-> (sugars + O2)
Why are mitochondria and chloroplast “semi-autonomous”?
- Each have their own genome
- Have their own ribosomes
- They replicate
- They have double membranes
- They have similar sizes and shapes
About the mitochondria?
- source of all cellular respiration
- two membranes; inner one has folds called cristae
- matrix is the “cytoplasm”
About chloroplast?
- two boundary membranes + internal thylakoid membrane
- stroma is the “cytoplasm**
- stacks of thylakoid are called grana
- photosynthetic reactions occur in the thylakoid and stroma
What are the roles of plastids?
Storage and pigmentation
What are the other types of plastids we learned about? (Labs)
- chromoplast - house pigments for organ colouration
- leucoplasts - no pigments
- amyloplast - starch storage
- protein plant - protein storage
What is cytoskeleton and the types?
Filamentous protein polymers
Types:
- microtubules
- intermediate filaments
- microfilaments
What is the function of cytoskeleton?
- cell shape
- cell polarity
- cell division
- cell movement and migration
- intracellular transport and cytoplasmic organization
About microtubules?
- polymer of a (alpha) / B (beta) -tublin dimers
- 13 protofilaments
- have plus and minus-ends, which gives them an inherent polarity
- switch between growing (polymerization) and shortening (depolymerization)
- must growth / shortening occurs at plus-ends
What are microtubule functions?
- cell shape and movement
- provide tracks for intercellular organelle movement
- attach to chromosomes during division to form the spindle
About microfilaments?
- polymers of actin
- two protofilaments form a helix
- also have a plus and minus-ends, which gives them an inherent polarity
- also grow by polymerization and shorten by depolymerization
- also most growth/shortening at +ends
